In this paper, we present an approach for facilitating user interaction on mobile devices, focusing on camera-enabled mobile phones. A user interacts with an application by moving their device. An on-board camera is used to capture incoming video and the scrolling direction and magnitude are estimated using a computer vision-based algorithm. The direction is used as the scroll direction in the application, and the magnitude is used to set the zoom level. The camera is treated as a pointing device and zoom level control in applications. Our approach generates mouse events, so any application that is mouse-driven can make use of this technique. The user is free to browse through large data sets on a limited size display with one hand, ideal for the mobile domain.

We present a multi-camera vision-based eye tracking method to robustly locate and track user's eyes as they interact with an application. We propose enhancements to various vision-based eye-tracking approaches, which include (a) the use of multiple cameras to estimate head pose and increase coverage of the sensors and (b) the use of probabilistic measures incorporating Fisher's linear discriminant to robustly track the eyes under varying lighting conditions in real-time. We present experiments and quantitative results to demonstrate the robustness of our eye tracking in two application prototypes.

Reliable detection and tracking of eyes is an important requirement for attentive user interfaces. In this paper, we present a methodology for detecting eyes robustly in indoor environments in real-time. We exploit the physiological properties and appearance of eyes as well as head/eye motion dynamics. Infrared lighting is used to capture the physiological properties of eyes, Kalman trackers are used to model eye/head dynamics, and a probabilistic based appearance model is used to represent eye appearance. By combining three separate modalities, with specific enhancements within each modality, our approach allows eyes to be treated as robust features that can be used for other higher-level processing.